Psychology - Biological approach

The biological approach (also known as the medical model) argues that all mental disorders are related to some change in the body. Mental disorders are like physical disorders (they are illnesses). The biological model of abnormality focuses on abnormal functioning of the nervous system and the genetic abnormalities that influence this.

There is evidence to suggest that mental disorders tend to run in families. To explain this using the biological approach we could say that it is due to the specific genes are inherited. To investigate how much genes influence mental disorders, psychologists study twins and concordance rates. Concordance rates refer to the presence of the same trait in both members of a pair of twins. Monozygotic twins share 100% of the same genes and dizygotic twins share 50% of the same genes. If concordance rates for a particular disorder were 100% for MZ twins and 50% for DZ twins, then we could say that the disorder has a purely genetic basis.

Evidence suggests that mental disorders may involve abnormal levels of neurotransmitters in the brain. For example, depression is associated with a reduced level of monoamines in the brain. Neurotransmitters are chemicals in the brain which send signals between one neurone and another across the synapse. Futhermore, people with depression appear to have low levels of serotonin and nor-adrenaline, and people with schizophrenia appear to have high levels of dopamine.

The brain is made up of several different structures and regions, all of which are devoted to certain actions and processes. Some evidence put forward by the biological approach suggests that mental disorders may be the result of structural abnormalites in the brain.